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An experimental and analytical study of the process of blown film extrusion was carried out. On-line measuring techniques were used to follow the dynamics and temperature profiles occurring in the process. The applicability of a mathematical model which includes a non-isothermal crystallization rate equation was tested. Subsequently, a new simplified model derived from a modified force balance was proposed and examined. Linear low density polyethylene, LLDPE, (melt flow index 1.0) provided by Dow Chemical Company was used in the experimental part of the study. On-line measurements for radius, thickness, velocity and temperature as a function of distance from the extrusion die were carried out, and their reliability was examined. The results indicated that these measuring techniques were sufficiently accurate to make the collection of on-line data a useful analytical tool. The measured profiles of radius, thickness, velocity and temperature were used to test the theoretical model for the tubular film blowing process. The apparent elongational viscosity, a key parameter for the theoretical simulation, was estimated and calculated from experimental data taken on a melt spinline and an inversion procedure developed for obtaining apparent elongational viscosities for melt spinning. This gave a Newtonian, temperature-dependent apparent viscosity equation. The heat transfer coefficient was estimated from measured temperature profiles on the blown film process. A computer simulation for semi-crystalline materials was carried out using the mathematical analysis for film blowing which appears in the literature plus a non-isothermal crystallization rate equation. The analysis was carried out by using the fourth-order Runge-Kutta method to solve the resulting differential equations. The predicted results were in qualitative agreement only with the experimental data. At the same time, several unexpected phenomena appeared in the simulation. Some of them have also been reported in the previous literature, but still no satisfactory interpretation is available. A modified physical approach based on a force balance led to the derivation and proposal of a new simplified model. From this modified analysis, an important and useful relationship between the external forces (i.e., the net takeup force and the inflation pressure) and the variation of radius and thickness of the bubble were determined. Based on the same initiaI conditions as that of the original model, the new model gave predictions which were in fair quantitative agreement with the on-line measurements. Finally, it was also found that the development of crystallinity strongly influences the final values of radius and thickness of the tubular film, two of the important specifications in industrial film processing. In other words, the effect of crystallization is so significant that it should not be neglected in modelling the tubular film blowing process.

The overall aim of this thesis is to describe the synthesisof branched aliphatic polycarbonates and show the potentialapplication of these polymers in the field of powder coatings.The characterization of the polycarbonates was facilitated bythe study of a series of bis-MPAdendrimers, which served asreference of perfectly branched polymers. In addition anε-caprolactone monomer with a bis-MPA pendant unit wassynthesized and polymerized in order to find an alternativesynthetic route hyperbranched polyesters. Cationic ring opening polymerization (CROP) of neopentylenecarbonate was utilized to synthesize a number of branchedpolymers. This monomer was chosen because the thermalproperties of poly(neopentylene carbonate) are promising forpowder coating applications. CROP enabled the synthesis ofbranched polymers, which are of great interest because of theirreduced melt viscosity and high functionality compared tolinear polymers. CROP of neopentylene carbonate, with a seriesof polyols including a hyper-branched polyester (Boltorn H30),in the presence of fumaric acid resulted in polymers withvaried degrees of branching and molecular weights ranging from2 000-100 000 g mol-1. Neopentylene carbonate was also used in the synthesispolycarbonate macromonomers possessing a polymerizablemethacrylate functional group at one of the chain ends. Inthjis case hydroxyethylmethacrylate was used as initiatopr inthe reaction catalyzed by methyl sulfonic acid. The MW of thismacromonomer was 2500 g mol-1and it was used to produce polymer brushes byfree radical and atom transfer radical polymerization(ATRP). An ε-caprolactone bearing a pendant bis-MPA wassynthesized and polymerized by Sn(Oct)2. Copolymerization with ε-caprolactone wasperformed to introduce linear segm,ents between the branchingpoints. The molecular weights of the homopolymer and thecopolymer were 3000 and 8000 g mol-1respectively as determined by Size exclusionchromatography (SEC) calibrated with polystyrene. SEC was used to analyze a series of bis-MPA dendrimers, andthe results were used to characterize the branchedpolycarbonates. The Mark-Houwink plots of the dendrimers wereproduced and used as reference in the characterization of thepolycarbonates. The thermal and rheological characterization of thepolycarbonates showed that the polymers were semi-crystallinewith Tgbetween 20-30 °C and Tmbetween 90-120 °C. Rheology measurementsshowed that the architecture had a considerable impact on themelt viscosity. Coating films were produced by UV curing of a series oflinear polycarbonates were functionalized with methacrylicgroups. The storage stability was tested for one week at 45°C, no coagulation of the particles was observed at theend of the testing period. The cured films showed good chemicalresistance and flexibility.

Effect of new curing and toughening agents

Soluble polymer supports that could be used in thermomorphic and latent biphasic systems have been prepared and analyzed for their potential application as supports for facilitated synthesis and catalysis. Phase selective solubilities were evaluated using polymers tagged with either visible dyes or fluorescent probes. Heptane/DMF, heptane/90% ethanol-water, heptane/ethyl acetate, heptane/ ethanol and heptane/tert-butanol solvent mixtures were all studied as examples of thermomorphic or latent biphasic systems. A range of polymers, including poly-(tert-butylstyrene) (PTBS), poly(alkylsiloxanes) (PAS), poly(dodecylvinylpyrrolidone) (PDVP), poly(didodecylvinylpyrrolidone (PDDVP), poly(isobutylene) (PIB), poly(octadecyl acrylate)s (PODA), and poly(octadecyl methacrylate)s (PODMA), were tested for hydrophobic phase selective solubility. The results of these studies were compared to prior work with polar and nonpolar poly(N-alkylacrylamide)s and polystyrene. Together with this prior work, these results have indicated that a wide range of polymers and solvent mixtures can be used for the recycling of soluble polymer-bound catalysts, reagents and sequestrants using either thermomorphic or latent biphasic separation strategies.Synthetic routes to terminally functionalized polyisobutylene oligomers, useful as supports in synthesis and catalysis, are also discussed and described. Such hydrocarbon polymers serve as highly soluble nonpolar analogs of well known poly(ethylene glycol) supports for synthesis and catalysis with the difference that the polymers are separated after a reaction by an extraction with alkane solvent. The synthesis of two polyisobutylene-supported phase transfer catalysts (PTC) are also described. These PTCs utilize the robust triazole functionality as a key synthetic step towards the preparation of the catalytic species. N alkylation of a PIB-supported triazole provides a direct route to the preparation of a PTC. Preparation of a tertiary phosphoninium salt containing a terminal alkyne allows simple attachment of the PTC to a PIB-supported azide via a triazole linker using Sharpless' Cu (I) [3 + 2] cycloaddition. These materials are active in catalyzing solid-liquid PTC and can be easily recycled by liquid-liquid extraction techniques.

<p>The overall aim of this thesis is to describe the synthesisof branched aliphatic polycarbonates and show the potentialapplication of these polymers in the field of powder coatings.The characterization of the polycarbonates was facilitated bythe study of a series of bis-MPAdendrimers, which served asreference of perfectly branched polymers. In addition anε-caprolactone monomer with a bis-MPA pendant unit wassynthesized and polymerized in order to find an alternativesynthetic route hyperbranched polyesters.</p><p>Cationic ring opening polymerization (CROP) of neopentylenecarbonate was utilized to synthesize a number of branchedpolymers. This monomer was chosen because the thermalproperties of poly(neopentylene carbonate) are promising forpowder coating applications. CROP enabled the synthesis ofbranched polymers, which are of great interest because of theirreduced melt viscosity and high functionality compared tolinear polymers. CROP of neopentylene carbonate, with a seriesof polyols including a hyper-branched polyester (Boltorn H30),in the presence of fumaric acid resulted in polymers withvaried degrees of branching and molecular weights ranging from2 000-100 000 g mol^-1.</p><p>Neopentylene carbonate was also used in the synthesispolycarbonate macromonomers possessing a polymerizablemethacrylate functional group at one of the chain ends. Inthjis case hydroxyethylmethacrylate was used as initiatopr inthe reaction catalyzed by methyl sulfonic acid. The MW of thismacromonomer was 2500 g mol^-1and it was used to produce polymer brushes byfree radical and atom transfer radical polymerization(ATRP).</p><p>An ε-caprolactone bearing a pendant bis-MPA wassynthesized and polymerized by Sn(Oct)₂. Copolymerization with ε-caprolactone wasperformed to introduce linear segm,ents between the branchingpoints. The molecular weights of the homopolymer and thecopolymer were 3000 and 8000 g mol^-1respectively as determined by Size exclusionchromatography (SEC) calibrated with polystyrene.</p><p>SEC was used to analyze a series of bis-MPA dendrimers, andthe results were used to characterize the branchedpolycarbonates. The Mark-Houwink plots of the dendrimers wereproduced and used as reference in the characterization of thepolycarbonates.</p><p>The thermal and rheological characterization of thepolycarbonates showed that the polymers were semi-crystallinewith T_gbetween 20-30 °C and T_mbetween 90-120 °C. Rheology measurementsshowed that the architecture had a considerable impact on themelt viscosity.</p><p>Coating films were produced by UV curing of a series oflinear polycarbonates were functionalized with methacrylicgroups. The storage stability was tested for one week at 45°C, no coagulation of the particles was observed at theend of the testing period. The cured films showed good chemicalresistance and flexibility.</p>